1. Technical Field
The present invention relates to automated carcass processing equipment. More particularly, the invention relates to apparatus and methods for stabilizing a moving carcass to present it at an accurately known moving position along a carcass rail relative to automated or robotic carcass processing equipment. By reliably stabilizing the location of each moving carcass, automated carcass processing equipment, such as carcass splitters and the like, can accurately and automatically perform carcass processing operations as the carcass continuously moves along the carcass rail.
2. Background Art
Meat processing facilities such as those that process hogs, operate on carcasses that continuously move along an overhead carcass rail. Each carcass is suspended, typically from its hind legs, from a trolley that rides along the overhead carcass rail or track. The trolleys are driven by a chain so that each carcass moves past each processing station at a speed set by the chain.
It is becoming more common for processing operations that were previously performed manually to be performed by automated equipment. For example, one step in carcass processing is to split the carcass vertically along the backbone. In many facilities, this splitting operation is now being performed with automated carcass splitters.
One such automated carcass splitting device is shown in U.S. Pat. No. 6,126,536 issued to Kielwasser on Oct. 3, 2000, which is assigned to Jarvis Products Company.
In order to properly process the carcass, it is essential for the automated equipment to accurately know the position of the carcass relative to the processing equipment. For example in a carcass splitter it is essential to know the position of the spine of the carcass so that the cut can be made along the centerline of the spine. Any deviation from that centerline by the cutting saw is extremely undesirable.
The position at the upper end of the carcass is generally more accurately known than the position of the lower end. This is because the upper end of the carcass is suspended from the trolley and the location of the trolley is determined by the chain driving the trolley along the carcass rail. However, even this position may not be perfectly known due to the distance below the rail where cutting begins and the fact that the carcass may swing forward and back. The trolley may even roll slightly ahead of the driving point by the chain. Accordingly, although the location of this upper end is known to reasonable accuracy, the location is not perfectly known.
The location of the lower end of the suspended carcass is even more uncertain. The chain may stop and start, or it may turn corners or the trolley may encounter imperfections in the carcass rail. All of these may cause the carcass to swing forward and back in a swinging motion parallel to the direction of motion of the chain. This motion causes great difficulty in automated processing operations, particularly processing operations that occur near the bottom end of the carcass away from the more accurately known reference point at the top end of the carcass.
In U.S. hog carcass processing facilities, it is common for the head of the animal to remain attached to one side of the carcass. The head acts as a heavy pendulum which can accentuate the swinging motion of the carcass as the carcass chain starts and stops.
The entry of the carcass into position before an automated processing machine is referred to as the “presentation” of the carcass to the automated equipment. It is desirable for this presentation to be accurate and consistent for each carcass so that an accurate cut or other processing operation may be completed.
Once the carcass is presented, the carcass processing equipment will typically have final positioning equipment to hold the carcass as the processing is completed. The present invention relates to improving the presentation, minimizing or eliminating swinging and assisting the processing equipment in accurate processing.
There have previously been attempts to control the position of the carcass relative to automated processing equipment. U.S. Pat. No. 6,126,536 issued to Keilwasser traps the carcass between back rollers (and/or slides) that engage the back of the carcass and smaller rollers (and/or slides) on the opposite side that engage and track the spine. Both the back rollers and spine rollers are extendable to contact the carcass and vertically movable to slide/roll down along the carcass as it is split.
The back side roller assembly engages the back of the carcass while the spine side rollers engage and track down along the spine along the inner side of the carcass. The roller assemblies on each side of the carcass act to move the carcass spine and thereby move the entire carcass slightly forward or back along the axis of the carcass rail (which is left and right relative to the splitting saw) as they move from top to bottom.
The splitting saw is located just above the roller assemblies so that the carcass spine is actively moved to the desired, accurate, position just before the saw cuts the spine and splits the carcass.
A particular advantage of the back rollers and spine roller alignment system is that the rollers initially are positioned relative to the carcass at the top of the spine, which is in the most accurately known position. The rollers then proceed from top to bottom, trapping the spine and the back of the carcass, so that the remainder of the spine and carcass move to the desired position just before the cut is made.
Although this design is effective, there remain difficulties and problems when cutting. An improved set of rollers to help with carcass alignment is shown in U.S. Pat. No. 6,468,146, also assigned to Jarvis Products Corporation.
Despite these improvements, the spine is not well defined at the top of the carcass and the spine rollers may not correctly engage it at the beginning of the cutting operation even if the carcass is correctly presented. Alternatively, the spine may not be perfectly straight and the rollers, which are attempting to track the spine, may inadvertently roll off that track producing a “miscut.” If the carcass is swinging or moving significantly, it may also prevent accurate cutting.
Despite these potential issues, the back roller/spine roller system described above is a significant improvement over designs such as that seen in U.S. Pat. No. 4,653,150 issued to Leining on Mar. 31, 1987 in which the carcass is held between a pair of vertically fixed guide plates. The back roller/spine roller system described above actively realigns the spine just before cutting. The Leining design simply traps the carcass in the position it is presented to the machine. The guide plates extend out from a frame to trap the sides of the carcass. The carcass position when it is trapped sets where the spine cut is made. The guide plates often trap the carcass in a crooked orientation, particularly where the carcass is swinging as it is presented to the machine. If the carcass is presented slightly rotated about a vertical axis, or if the spine is slightly crooked, the saw cannot accommodate or correct the incorrect alignment.
It will be understood that the back rollers and inner spine rollers of the design shown in U.S. Pat. No. 6,126,536 move both vertically and horizontally. The horizontal motion is to track the carcass as the carcass continuously moves along the carcass rail. The vertical motion is to actively align the spine with the saw, which is following closely behind. This allows the splitting operation to proceed while the carcass is continuously moving along the carcass rail.
Nonetheless, if a carcass is rapidly swinging or moving as it is presented to the machine, the initial grasping of the carcass by the rollers at the top may be misaligned and the rollers will continue to be misaligned as they track the carcass. Alternatively, the spine of the animal may be shaped such that the rollers roll off the spine. The subsequent cutting and processing operations on the carcass will not occur in the correct location if the rollers are not correctly positioned relative to the spine of the carcass.
The present invention is intended to address these problems. The present invention prevents the carcass from swinging. In the preferred embodiment, it also acts to straighten the centerline of the carcass so that all parts of the carcass are in a more accurately known position. As will be described more fully below, the present invention stabilizes the carcass by grasping the carcass at a lower position to prevent swinging and then acts to pull down on the bottom end of the carcass. This has the effect of more accurately positioning the bottom end of the carcass to a known location just as the upper end is at a known location. The downward pull on the carcass then acts to straighten the spine of the animal, which provides improved performance of the tracking of the spine by the roller guide system described above.